This invention relates generally to an arrangement for heating the operator's cabin of a machine driven by an internal combustion engine, more particularly the driver's cabin of a motor vehicle, and includes a hydraulic pump driven by the engine for withdrawing engine oil from the lubricating- or cooling-oil system of the engine, a heating system connected into the oil distribution system and including a throttling element downstream of the hydraulic pump for increasing the temperature of the engine oil passing therethrough, an oil/air heat exchanger located in the operator's cabin and coupled into the heating system downstream of the throttling element, and an adjustable control element for controlling flow of the engine oil to the heat exchanger or through a line by-passing the heat exchanger. Such a heating arrangement is of particular advantage in air-cooled internal combustion engines.
U.S. Pat. No. 4,352,455 (Moser et al), dated Oct. 5, 1982, and commonly owned herewith, discloses a heating arrangement generally of the aforedescribed type in which the lubrication- or cooling-oil circuit and the heating circuit are completely separated at least from the intake side of the hydraulic pump. Thus, although slightly heated engine oil is available in the heating system heat exchanger when the engine starts operating, a desireable higher temperature is not established at the lubricating points of the internal combustion engine until the entire lubricating oil supply has been gradually heated. In this prior heating arrangement, a partial quantity of the lubricating oil supply must effect an accelerated rise in temperature in the heating system heat exchanger through repeated throttling. However, since the oil is heated only gradually it may prove detrimental to the oil distributing points. Moreover, a special control element is required for regulating this repeatedly throttled partial quantity of oil.